A sig alert went out at 11:30 p.m. on Thursday following a multi-car collision on westbound Highway 4 near Bailey Road in Bay Point, according to the CHP.
All lanes are currently blocked.
Six vehicles were involved, CHP reported. Four of them required a tow truck to remove them from the scene.
At least one vehicle was on fire, possibly due to an explosion, and another had rolled over.
This story is developing. Check back for updates.